This Workout Trend Could Be Harmful to Your Health

If you’re a fan of exercise DVDs, you may want to press pause before beginning your routine. According to a new study conducted by Oregon State University, some fitness videos might diminish the effectiveness of at-home workouts, and could even cause both psychological and physical harm.

The researchers examined the imagery and language of 10 popular instructor-led DVDs released between 2011 and 2014, finding that the instructors’ appearance and their motivational statements were particularly harmful to users. The results of the study are published in Sociology of Sport Journal.

The majority of the instructors in the DVDs were found to be slender, Caucasian females wearing revealing attire, which emphasizes physical appearance over improved health, according to the researchers. It also perpetuates unrealistic body images, and leads users to expect impractical results.

The instructors’ motivational statements were also problematic, with one in seven found to be negative and demotivating. The statements, which included phrases such as “You better be sweating,” and “You should be dying right now,” encourage comparison, and don’t take into consideration users’ varying fitness levels.

“You’re inviting into your home these images and messages that could make you feel bad about yourself, and ultimately hinder your efforts to improve your health,” Brad Cardinal, lead author of the study, said in a statement. “If the experience is not positive, the likelihood the person is going to continue with an exercise program diminishes.”

The DVDs, which make up a $250 million a year industry, could also be physically dangerous. Many of the instructors appear to have few or no credentials, and the videos, while typically marketed to beginners, are often made up of intermediate or advanced movements.

If you prefer this type of exercise, don't sweat it—there may be a few viable options. Look for workout DVDs produced by verifiable, credible sources, Cardinal tells RealSimple.com.

"This might include an exercise leader who has one or more degrees in a related field or holds a credible exercise certification," he said. But watch out for over-the-top marketing promises: "At present, this is a largely unregulated industry, so this is a challenge. The claims made can be exaggerated."